As far as "good luck" goes, he may be thinking of a scene in the 1963 film The Great Escape where this happens in reverse- escaped British PoWs are captured when a Gestapo officer wishes them "Good luck" in English and one of them instinctively replies "thank you".

I have seen claims (for instance in This Great Escape: The Case of Michel Paryla by Andrew Steinmetz, and The RAF's French Foreign Legion by G.H. Bennett) that this incident is based on the real-life case of the French escapee Sous-Lt. Bernard Steinhauer, who was fluent in English and German as well as his native French and who was captured at Saarbrücken station after replying in English to an English greeting by a Gestapo officer- although sources differ on the exact phrase used.

(Like most of those who escaped in the breakout from Stalag Luft III, Sous-Lt. Steinhauer was shot a few days later)